In this one experiment, half the test participants were fed ice-cream immediately upon waking. They then all had to sit down and perform some mental tasks on a computer. The participants who ate the ice-cream performed significantly better at these tasks than those who didn’t eat ice-cream.

But why?

Prof. Koga suspects the positive mood boost we get from eating ice-cream combined with the shock of eating something cold could all contribute to increased energy and alertness.

Eating the creamy treat first thing in the morning might not be the smartest move if you're trying to stay healthy. Ice-cream is well known for high quantities of fat and sugar. So if you’re after a similar affect without the calories you can try drinking cold water when you wake up which also helps boost alertness.